Electrum

Electrum is a lightweight Bitcoin client, based on a client-server protocol. It was released on november 5, 2011.

Main features:

• Encrypted wallet
• Deterministic key generation. If you lose your wallet, you can recover it from its passphrase.
• No blockchain download; the client requests that information from a server
• Private keys are not shared with the server.
• Firewall friendly: The client does not need to open a port, it simply polls the server for updates.
• No single point of failure: The server code is open source, anyone can run a server.
• Python. Very compact code, easy to contribute.

Brain Wallet

Electrum uses a type 2 deterministic key generation algorithm. This means that all the keys are derived from a seed.

Electrum makes it easy to memorize its seed, because it uses a mnemonic code.

Example:

• hexadecimal: 8a44dfd6ad4f687b5e3c80563c327027
• mnemonic: "shade weave eternity kept true tangle new talk clay warmth fish match"

Export and import addresses

You can export your private keys using the 'addresses' command:

$ ./electrum addresses -ak
Password:
1LGoehbyeX4QBEPK1a6dhyaoMQZfqg5LKX:5JBSttEGhjEcPidSovW66Rin2EZ6LEHZ2qx8Pu2RqqNaDTBVWaF   
1KcsBJa2cCxVkGJfSsg5bUeXN7Y5uLa8mP:5KiP4uiNT6KG8jnXbainCM8rDWRrgxt3PAyut4FFpDoCo1Rh6VM   
1PXsn7LVXTccGhJPTUL8r2EGB4fF9kvex3:5Kj8mvBJReyk8xEBMx5cTnciQCxto5JmudiTPkqwMcd61Kf1Jqc   
1KteSFTAphyByLTtUfFiVQ9s7fMVmx7c2h:5JeZ3FTbWcksLt3PKydd5U9p952UQRHwv3LoxzCA9LZ7V2bku5p   
1GE5ZChAobeTEPLHDCDDKTSg3XvLkcQFjS:5JwtGEygTwF2nouhRVzW3w5DWZd1sCgxLtnd1v51wjkbUrp5sqH   
12YNehfAoYTiwjTXULwaZqTCauu2D61fq6:5Jvcq19ePCXKcVun4n7US99CsrEByUK2kgxXBA3rBVBqYZjhfwD  [change] 

The option -a means: 'list all addresses' The option -k means: display the private keys

You can also import addresses into an electrum wallet, with the 'import' command:

$ ./electrum import 1LGoehbyeX4QBEPK1a6dhyaoMQZfqg5LKX:5JBSttEGhjEcPidSovW66Rin2EZ6LEHZ2qx8Pu2RqqNaDTBVWaF
keypair imported

Note that imported keys do not belong to the deterministic sequence of your wallet; if you import keys in a wallet, you must backup it up!

Screenshot

Security

See Thin Client Security

links

• homepage: http://ecdsa.org/electrum
• source code: https://gitorious.org/electrum
• download: git clone git://gitorious.org/electrum/electrum.git